Heretofore, heater stoves have been developed utilizing metal fireboxes and spaced metal walls defining air passages in which air may be circulated by a blower such as disclosed in U.S. Pat. No. 4,092,976. However, the problem arises that the metal walls radiate heat very rapidly and the heat from the fuel burned is distributed in a relatively short period of time at a high temperature. If the stove is throttled down, to spread out the burning time, combustion is incomplete and detrimental gases accumulate in the flue and chimneys which requires periodic cleaning and present a hazardous fire problem if left to accumulate. Incomplete combustion also results in inefficient use of the fuel. Furthermore, such heater stoves become very hot with or without use of a blower presenting a danger of hazardous burns to small children.
Other wood and coal burning stoves have utilized ceramic walls which absorb the heat from the fuel being burned and distribute the heat by radiation at a lower temperature. However, the initial response of such stoves is very long during initial heatup, and provide adequate heat only after the fire has burned a considerable amount of time. The combination of a firebox having metal and ceramic walls is also known which heats by natural convection and radiation. However, the initial response time is still slow. Shipping and distribution of such ceramic stoves is troublesome owing to their size and extremely heavy construction making them difficult and expensive to ship and distribute.
Accordingly, an important object of the present invention is the provision of heater stove apparatus having a rapid initial response and which, after reaching a desired temperature, may be controlled to distribute heat gradually at a low temperature for a more even distribution of heat.
Yet another important object of the present invention is to provide heater stove apparatus which distributes heat at a low temperature over a longer time interval than a conventional double-walled metal stove while affording the same degree of rapid initial response in heating an interior space.
Still another important object of the present invention is to provide wood heater stove apparatus having rapid initial response capability and thereafter gradual response capability at a low temperature without the attendant problem of incomplete combustion accumulation of detrimental gases as found in prior heater stoves.
Still another important object of the present invention is to provide a heater stove apparatus which includes an inner metal firebox and individual ceramic mass on site in a home to provide forced convection and radiant heat at an affordable cost.
Still another important object of the present invention is to provide apparatus for adapting an existing metal heater stove into a convection and radiant heater by constructing a ceramic outer shell about walls of the metal firebox, particularly, on site in a home.